1. The Field of the Invention
Implementations described herein relate generally to high-throughput electrophysiology culture system and, more particularly, to an electrophysiology culture system with a culture plate having an integrated monolithic microelectrode array plate.
2. Related Art
In vitro electrophysiology culture systems having microelectrode arrays (MEAs) can provide important insights into networks of electrically active cells. MEA-based electrophysiology culture systems can be configured to concurrently monitor single cell and network level activity over extended periods of time and without affecting the cell culture under investigation. Since their instrumental role in the 1993 landmark discovery of spontaneous waves in a developing retina, the variety and scope of MEA-based electrophysiology applications have dramatically expanded. Recently, for example, MEA-based electrophysiology culture systems have been used to investigate the suppression of epileptic activity and in the study of novel plasticity mechanisms in cultured neural networks. Advances in cell culture preparations have similarly led to applications for MEA-based electrophysiology culture systems in the fields of drug screening, safety pharmacology, and biosensing.
Present day MEA-based electrophysiology culture systems are typically designed around small-footprint, single-well devices. However, the complete analysis of complex cellular systems and processes can require repeated experiments. The number of experiments can increase quickly when considering multiple variables, such as stimulus size, compound type, dosage strength and the like. Thus, the small-scale format of traditional MEA systems presents problems due to excessive experimental and statistical sizes, whereby the serial nature of these devices can render even basic investigations time and cost prohibitive. As one illustrative example, a researcher examining the effect of pythrethroids on two-hour spontaneous activity recordings can require 8 doses of permethrin, with an N of 6 for each dose. With traditional MEA-based electrophysiology culture systems, this very simple experiment can require over $5,000 in MEA-based electrophysiology culture plates (or “MEA culture plate”) and 50 to 60 man-hours. The time investment can further increase with the logistics of culturing, maintaining, and testing dozens of individual specimen.
Thus, design of a high-throughput MEA culture plate is highly desirable. However, conventional manufacturing techniques fall short of enabling their manufacture by merely scaling up a conventional design. For high-throughput investigations, large-area, American National Standards Institute (ANSI)/Society for Lab Automation and Screening (SLAS)-compliant plates can be important as industry standard compliance can provide compatibility with other high-throughput instrumentation such as plate readers and robotics handlers. Conventional MEA culture plates, some of which can be subdivided into a small number of wells (e.g., about 6), can cost from about $150 to about $500 and are not easily scaled to high well count plates without prohibitive manufacturing costs. Specifically, the development of an ANSI/SLAS-compliant, high-throughput MEA culture plate presents two major challenges: (1) ensuring 100% yield of widely distributed micro-scale electrodes and (2) developing cost-effective manufacturing processes to provide inexpensive high-throughput MEA culture plates. The microfabrication industry has traditionally addressed these issues by fabricating thousands of micro-scale devices in parallel and then individualizing each unit, with the results of reducing the per-unit cost of each device and ensuring that non-working units can quickly be identified and discarded. The working units are then packaged using wafer-level packaging technologies or individual unit-level technologies that have been optimized for cost-effectiveness. However, for high-throughput MEA plate fabrication, the plate size is much greater than traditional micro-scale devices, increasing the likelihood that a single microelectrode may fail, rendering the entire plate a non-working unit. Additionally, if only single plate can be microfabricated on one wafer, the cost advantage is lost versus the batch fabrication of micro-scale-sized devices described above.
Thus, broad access to neural information along with the minimally invasive nature of a MEA-based electrophysiology culture systems renders them a potentially valuable tool for discovery. However, the throughput of MEA-based electrophysiology culture systems needs to increase to keep pace with the requirements of today's researchers. Accordingly, a need exists for improved MEA-based electrophysiology culture systems that provide for high-throughput applications and reliable large-area microfabrication methods to manufacture the MEA plates and, ultimately, the assembled MEA-based electrophysiology culture plates.